Casing for a watch



FIG. 1 is a perspective view of a casing for a watch showing my new design;

FIG. 2 is a left side elevational view thereof;

FIG. 3 is a top plan view thereof;

FIG. 4 is a right side elevational view thereof;

FIG. 5 is a front elevational view thereof;

FIG. 6 is a rear elevational view thereof; and,

FIG. 7 is a bottom plan view.

The broken line showing of a crown is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a "casing for a watch," as shown and described. 